Cooperation of Two Metal Centers in a CO ₂ Electroreduction Catalyst: Flexible Electron Manipulation and Adaptive Coordination on a Dinuclear Cobalt Complex

Abstract Metal complexes with flexible redox and coordination properties possibly act as ingenious electrocatalysts to activate stable molecules such as CO ₂ . To date, most studies have focused on mononuclear complexes in electrochemical CO ₂ reduction (eCO ₂ R). However, the development of electrocatalysts that operate at low overpotentials while maintaining high selectivity remains a critical challenge. Herein, it is demonstrated that the use of a dinuclear metal complex exhibiting cooperation of two metal centers can be an effective strategy for addressing this issue. The focused catalyst is a Co ^II dinuclear complex ( 2 ) bearing two Co ^II ions in close proximity, whose coordination environment is similar to that of a typical mononuclear complex, Co ^II tetraphenylporphyrin ( 1 ). Based on experimental and computational studies, it is clarified that 2 exhibits simultaneous two‐electron reduction prior to CO ₂ activation, which allows bypassing the reaction step that hinders the catalytic cycle on 1 . Furthermore, metal‐to‐metal electron transfer and a CO ₂ ‐derived intermediate bridging over two metal centers are found in the catalytic cycle of 2 , which would contribute to low activation barrier. It is then concluded that the cooperative functions of the two metal centers are the key to the efficient eCO ₂ R performance.